1. Field of the Invention
This invention relates to a semiconductor device having a capacitor.
2. Description of the Related Art
Recently, ferroelectric memories in which a ferroelectric film is used as a dielectric film of a capacitor, that is, FeRAMs (Ferroelectric Random Access Memory) have been developed.
In manufacture of ferroelectric capacitors, various processing in a reducing atmosphere is performed, such as processing a capacitor by RIE (reactive ion etching), deposition of an interlayer insulating film by CVD (chemical vapor deposition), and formation of a contact hole by RIE. Therefore, to prevent reduction of the capacitor insulating film (dielectric film), it is important to prevent diffusion of hydrogen contained in the reducing atmosphere into the capacitor.
Therefore, adopted is a method in which a capacitor is covered with hydrogen-barrier films to prevent diffusion of hydrogen into the capacitor. For example, in Jpn. Pat. Appln. KOKAI Pub. No. 11-54718, a hydrogen-barrier film such as a TiAlN is provided directly under a bottom electrode of a capacitor, and a top surface and side surfaces of the capacitor are covered with a hydrogen-barrier film, such as an aluminum oxide. Thereby, each capacitor is individually covered with hydrogen-barrier films.
However, Jpn. Pat. Appln. KOKAI Pub. No. 11-54718 only proposes a measure to prevent diffusion with respect to individual-capacitors. In a ferroelectric memory, there are cases where two capacitors which are related in circuitry are arranged adjacent to each other. In such cases, it is difficult to obtain an optimum structure even by using the above prior art. It is an important object how to realize an optimum structure having a function of preventing diffusion of hydrogen with respect to two adjacent capacitors.